We developed a new transparent polymer optode based on polymethacrylate with Zr(IV) and alizarin red complex immobilized into it for digital colorimetric and solid-phase spectrophotometric ...determination of fluoride anions. The matrix changes its colour from purple to yellow after it contacts fluoride anion. We developed a processing algorithm for coloured images which helps calculate mean value for the RGB colour-coordinate system in a selected optode image and translates it into a fluoride concentration value. The analytical signal of the suggested method has a linearity range of 0.1–30 mg⋅L−1 with the detection limit 0.03 mg⋅L−1. Compared to other methods, the modified polymethacrylate matrix is actually a ready-to-use colorimetric system offering rapid results for drinking water quality control.
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•Spectrophotometric abilities of Zr(IV) and alizarin red complex immobilized into polymethacrylate matrix.•Combination of transparent polymethacrylate sensor and digital processing of colour.•Smartphone-based image processing for colorimetric determination of fluoride anions.•Digital colorimetric and solid phase spectrophotometric determination of fluoride anions.•Portable analytical unit for colorimetric rapid analysis of water.
This paper describes a simple colorimetric method for determination of Brilliant Blue, Sunset Yellow, Ponceau 4R and Tartrazine using transparent polymer optode. The method provided acceptable linear ...ranges 0.01–3.0 mg L−1 with correlation coefficients higher than 0.995 under the optimal conditions. Commercial beverages and juices containing different amounts of food dyes were analyzed and the results were compared to those obtained by HPLC.
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•Visual and spectrophotometric determination of food colourants.•Portable analytical device for in situ rapid analysis without pretreatment.•Solid phase extraction of food colourants into transparent polymer matrix.
This work suggests using Cu(II) - neocuproine redox system immobilized into transparent polymethacrylate matrix for assessment of antioxidant capacity using CUPRAC method. The method we developed ...makes it possible to quantify the content of the antioxidants in the concentration range of 5.9 × 10−8–9.1 × 10−5 M. The sensor was tolerant to pH variations and painting, and used for the antioxidant capacity determination values of some commercial medicinal tinctures without pretreatment.
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•Spectrophotometric abilities of system Cu(II)-neocuproine immobilized into polymethacrylate matrix.•Visual and spectrophotometric determination of antioxidant capacity using optode•Portable optode for in situ rapid analysis
This is a description of the tracer analysis method involving colorimetric and fluorescent measurements based on solid phase extraction of rhodamine into transparent polymethacrylate matrix. ...Concentration of rhodamine in PMM is measured as spectrophotometric absorption level at 535 nm and fluorescence at 554 nm. The calibration graphs are linear within the ranges 0.02–0.10 mg∙L−1 and 0.002–0.06 mg∙L−1 and detection limits 0.014 mg∙L−1 and 0.0005 mg∙L−1 are calculated for colorimetric and fluorescent measurements, respectively. The method has been successfully used for determination of rhodamine in groundwater.
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•Solid phase extraction of rhodamine•Spectrophotometric/fluorimetric determination of rhodamine•Novel optical sensor for tracer analysis
This article presents solid-phase spectrophotometric method of bromate determination using methyl red immobilised into transparent polymethacrylate matrix. The method is based on oxygenation of the ...indicator immobilised into the matrix by a bromate. We discovered the optimal conditions for bromate determination, studied the effect of interference of the foreign ions, and evaluated the analytical performance of the suggested method. The method we developed makes it possible to quantify the content of a bromate in the concentration range of 0.1-1.0 mg·L
−1
with the limit of detection 0.01 mg·L
−1
. The mean relative standard deviation of the results was ≤1.2%, which confirmed reproducibility of this assay technique. We demonstrated usability of the suggested method for detection of bromates in drinking water using solid-phase spectrophotometry without any preliminary sample preparation. Polymethacrylate matrix with methyl red immobilised into it can be used as a ready-made analytical form for the rapid visual bromate determination test.
A colorimetric sensor is proposed for the determination of cobalt. It is prepared by immobilizing 1-(2-pyridylazo)-2-naphthol (PAN) in an optically transparent polymethacrylate matrix. The conditions ...for determining cobalt by the proposed colorimetric sensor are found in the study of the complexation of cobalt with a PAN-modified polymethacrylate matrix. The determination is based on the interaction of the sensor with a cobalt solution at pH 4 for 5 min, followed by the measurement of absorbance at 620 nm. The sensor ensures the determination of 0.05–0.50 mg/L of cobalt with the detection limit 0.03 mg/L. It is demonstrated that the sensor can be used for the determination of cobalt in the Cyanocobalamin medical preparation and potable water.
Procedures for the iodometric solid-phase spectrophotometric determination of nitrite and selenium( IV) using a polymethacrylate matrix are proposed. The procedures are based on the reaction of ...nitrite and selenium(IV) with iodine in an acidic medium with the release of free iodine in amounts equivalent to those of the substances to be determined, extraction of the iodine formed with a polymethacrylate matrix, and measurement of absorbance of the matrix at 370 nm. The developed procedures ensure the determination of 0.01–0.12 mg/L of nitrite and 0.05–0.40 mg/L of selenium(IV) with limits of detection of 0.005 and 0.03 mg/L, respectively. It was shown that the proposed procedures can be applied to the determination of selenium(IV) in mineral water and nitrites in vegetables and soil.
A procedure is proposed for the kinetic solid-phase spectrophotometric determination of thiocyanate using a polymethacrylate matrix. The procedure is based on the Landolt reaction between Crystal ...Violet immobilized in a polymethacrylate matrix and a bromate oxidizer, accompanied by the discoloration of the indicator in the matrix. During some induction period after the introduction of thiocyanate into the test solution, the dye in the matrix is not discolored. The duration of the induction period is proportional to the concentration of thiocyanate in the solution. The change in the color of the polymethacrylate matrix was recorded by measuring its absorbance at 600 nm. The developed procedure ensures the determination of thiocyanate in the concentration range 0.025–12 mg/L, depending on the Crystal Violet concentration in the matrix. The limit of detection calculated according to the 3
s-
test is 0.02 mg/L with the indicator concentration in the matrix of 0.06 mg/g. A possibility of using the proposed procedure for the determination of thiocyanate in near-wellbore water is shown.
Abstract Objective: to assess the relative level of mRNA of proinflammatory cytokines IL-1β and IL-17A, toll-like receptors 2 and 4 types and the transcription factor NF-KB in the epithelium of the ...oral cavity in children with diseases of the central nervous system, blood system, respiratory organs, and in children with mental disorders. Object and methods: the molecular-genetic study by polymerase chain reaction with reverse transcription real-time (RT-PCR) mRNA expression of the genes TLR2, TLR4, NF-KB, IL-1β and IL-17A in the epithelium of the oral cavity in 93 children with disabilities and 25 children with chronic catarrhal gingivitis without associated pathology in age from 12 to 15 years. Results: In children with special needs there is the rise of transcription activity of membrane TLR2 and TLR4 in all study groups except the group of children with mental disorders. Activation of pattern recognition receptors naturally causes transcriptional induction of the gene NF-KB and regulated by it the proinflammatory cytokines IL-1β and IL-17A by the buccal epithelium: expression levels of mRNA of IL-1β and IL-17A in children with central nervous system diseases were increased by 8.9 and 7.7 times (P < 0.05), respectively, in children with mental diseases the level of IL-17A was increased by 2.2 times (P < 0.05) in comparison with the control, in children with respiratory diseases and diseases of the blood system the expression of IL-1β was increased by 6.5 and 2.9 times (P < 0.05), respectively, IL-17A – 3.8 and 3 times (P < 0.05) as compared to control. Conclusions: discovered in the work transcriptional induction of the genes TLR2 and TLR4 and subsequent activation of Nf-kB and production of proinflammatory cytokines IL-1β and IL-17A d is one of the mechanisms that explains the more severe course of periodontitis in children with disabilities as compared to patients with periodontitis and without comorbidities.
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